In order to lower inter-cell interference and further improve the spectrum efficiency, the Fractional Frequency Reuse (FFR) technology has been introduced to the Worldwide Interoperability for Microwave Access (WiMAX) system, and an underlying idea thereof lies in transmission of data between adjacent cells in a fractional frequency reuse mode. FIG. 1 is a schematic principle diagram of FFR, and as illustrated in FIG. 1, an area denoted in a horizontal-line shape in the figure can be shared by three adjacent cells without any limitation on transmission power, so the area denoted in the horizontal-line shape is located in a frequency band with a frequency reuse coefficient of 1; and in the left diagram of FIG. 1, areas denoted in a mesh shape of the three cells are located respectively in different frequency bands, and the area denoted in the mesh shape of any cell will not be used by other cells, so the areas denoted in the mesh shape are located in frequency bands with a frequency reuse coefficient of 3; and other frequency bands in the right diagram than the frequency band where the area denoted in the horizontal-line shape is located have a reuse coefficient of 3/2.
In the Long Term Evolution (LTE) system, in order to achieve same-frequency networking as far as possible, the LTE standard decides the adoption of the Inter-Cell Interference Coordination (ICIC) technology and defines related load information, e.g., a High Interference Indicator (HII), an Overload Indicator (OI), a Relative-narrowband Tx Power indicator (RNTP), etc., to be exchanged via an X2 interface (an interface between eNodeBs) in the ICIC technology. In the ICIC technology, a decision on limiting the use of resources is made based upon load information generated in a current cell and received load information generated in an adjacent cell and is notified to a scheduler, a power controller and other modules to achieve the purpose of inter-cell interference coordination.
After receiving the decision on limiting the use of resources made by an ICIC module, the scheduler, the power controller and the other modules allocate frequency-domain resources and power resources for respective scheduled users in the current cell in compliance with the limitation to thereby coordinate/alleviate inter-cell interference.
As can be seen from the foregoing description, both the FFR technology and the ICIC technology are implemented by limiting the use of frequency resources and power resources of an adjacent cell, that is, the foregoing solutions only focus on frequency-domain and power resources, and take into account interference coordination over only these two dimensions.
Furthermore, in a beam shaping-enabled cell, inter-cell interference coordination/avoidance can be achieved in beam coordination solutions which can be divided into static beam coordination, dynamic beam coordination and scheduling and other solutions in accordance with beam coordination modes and beam coordination periods, but a general idea of beam coordination is to allocate mutually orthogonal time and frequency resources for users in the same beam direction in adjacent cells to thereby achieve the purpose of beam coordination, that is, alleviating interference. FIG. 2 is a schematic principle diagram of static beam coordination which illustrating a static beam coordination solution, and in FIG. 2, resources of an orthogonal frequency division multiplexing system are divided into four mutually orthogonal sets, and users in respective cells are also divided into four mutually orthogonal sets depending on direction information of the users, and then beam coordination is achieved by establishing a mapping relationship between the sets of users and the sets of resources, where the mapping relationship between the sets of users and the sets of resources satisfies the following condition:
Resources belonging to different sets of resources are allocated to the greatest extent for users belonging to the same set of directions in adjacent cells to thereby achieve the purpose of allocating mutually orthogonal resources for the users in the same direction in the adjacent cells. In FIG. 2, direction information of users in areas numbered 1 and 2 belongs to the same set of users, and space-domain beam coordination to avoid same-frequency interference can be achieved by allocating a resource in a set of resources 1 for the users in the area numbered 1 and allocating a resource in a set of resources 2 for the users in the area numbered 2.
A drawback of the prior art lies in that in the foregoing various interference alleviation solutions of the orthogonal frequency division multiplexing system, either coordination over frequency-domain, power, frequency and power resources alone or space-domain beam coordination alone is taken into account, but these methods generally do not take into account specific characteristics of the Time Division Duplex (TDD) system and thus also do not take into account the specific characteristics of TDD in combination with the foregoing solutions to achieve a solution to joint interference alleviation in a plurality of resource dimensions.